Goldilocks Planets (grid)
Since the first confirmation of an exoplanet orbiting a sun-like star in 1995, and with only a few, narrow slices of our Milky Way galaxy so far surveyed, we’ve already struck many rich veins. A recent statistical estimate places, on average, at least one planet around every star in the galaxy. That means there's something on the order of a trillion planets in our galaxy alone, many of them in Earth’s size range.
"This porridge is too hot," Goldilocks exclaimed.
So she tasted the porridge from the second bowl.
"This porridge is too cold."
So she tasted the last bowl of porridge.
"Ahhh, this porridge is just right!" she said happily.
And she ate it all up.
The habitable zone (or Goldilocks zone) is the area around a star where it is not too hot and not too cold for liquid water to exist on the surface of surrounding planets.
Planets in the habitat zone are what scientists hope will lead us to water––and one day life.